HttpClientFactory For netcore And framework

NUGET Install-Package HttpClientFactory

supported netcore2.0 and framework4.5+

Why need HttpClientFactory?

As you know, HttpClient has a trap for using!

1. if not Singleton, each instance of HttpClient will open a new socket connection and on high traffic sites you can exhaust the available pool and receive a System.Net.Sockets.SocketException
2. if Singleton,HttpClient doesn't respect DNS changes!

So how to use HttpClient correctly？

//useage 1： same Host use same HttpClient
PerHostHttpClientFactory perHostHttpClientFactory = new PerHostHttpClientFactory();// can be static
//or you can change default timeout for perFactory
PerHostHttpClientFactory perHostHttpClientFactory = new PerHostHttpClientFactory(TimeSpan.FromSeconds(10));
HttpClient client = perHostHttpClientFactory.GetHttpClient("http://www.baidu.com");

//useage 2： per url use per HttpClient
PerUrlHttpClientFactory perUrlHttpClientFactory = new PerUrlHttpClientFactory();
//or you can change default timeout for perFactory
PerUrlHttpClientFactory perUrlHttpClientFactory = new PerUrlHttpClientFactory(TimeSpan.FromSeconds(10));
HttpClient client = perUrlHttpClientFactory.GetHttpClient("http://www.baidu.com");

//useage 3： per proxy use per HttpClient
PerHostHttpClientFactory perHostHttpClientFactory = new PerHostHttpClientFactory();
//or you can change default timeout for perFactory
PerHostHttpClientFactory perHostHttpClientFactory = new PerHostHttpClientFactory(TimeSpan.FromSeconds(10));
HttpClient client = perUrlHttpClientFactory.GetProxiedHttpClient("http://127.0.0.1:8080");

Easy to implement

	public class XXXHttpClientFactory : HttpClientFactoryBase
    {
        protected override string GetCacheKey(string key)
        {
            return key;
        }
				
				
		protected override HttpClient CreateHttpClient(HttpMessageHandler handler)
        {
            return new HttpClient(handler)
            {
                Timeout = TimeSpan.FromSeconds(20),
            };
        }

        protected override HttpMessageHandler CreateMessageHandler()
        {
            var handler = new HttpClientHandler();
            handler.Proxy = new WebProxy("xxx");
            return handler;
        }
    }

Remark

1. Default Timeout is TimeSpan.FromSeconds(100)
2. Default ConnectionLeaseExpired is TimeSpan.FromMinutes(1)